1. Field of the Invention
The present invention relates to bicycle technology and more particularly, to a power-assisted bicycle with a gear shift smoothening function that facilitates smooth gear shifting, providing better riding comfort.
2. Description of the Related Art
When shifting gears (gearing up or gearing down) during riding of a conventional power-assisted bicycle, the pedaling rate will be suddenly changed. For example, the pedaling rate will be reduced suddenly after an up shift, or increased suddenly after down shift. However, the rider cannot know in advance when the microcomputer of the power-assisted bicycle will shift gears. Further, the pedaling torque will also be changed suddenly after a gear shifting operation. The sudden change of pedaling rate after a gear shifting operation will make the rider feel awkward and uncomfortable.
Further, because the rider does not know when gear shifting occurs during riding, the rider may pedal the pedals with force or a high assistant power may be provided during gear shifting, causing the chain to become overtensioned and leading to unsmooth shifting or a shifting failure. Therefore, enabling the rider to know in advance when shifting gears and allowing adjustment of the assistant power are important factors for smooth gear shift operations.